ABSTRACT
This work presents a detailed geology of Enugu-Ngwo and environments. The study area is bounded by latitudes 7o23’N and 7o30’N and longitude 7o23’E and 7o30’E.The area extent covers approximately 167.7km. Three distinct formations such as Enugu Shale, Mamu Formation and Ajali Formation are exposed in the area.
The Enugu Shale is carbonaceous, fissile, grey and jointed with beds of siltstone and clay. The Mamu Formation contains a distinctive assemblage of sandstone, Shale, mudstone and sandy shale with coal seams at several horizons. Field measurement shows that it has average dip amount of about 5.6o in the south western direction and average strike direction of about 126oAzimuth. Results from sieve analysis show that Mamu Formation is moderately well sorted to moderately sorted, coarse skewed to strongly fine skewed and very leptokurtic to extremely lepkurtics. The plastic and liquid limit test show that the shale has plasticity of 19% and liquid limit of 29%.
The Ajali Sandstone is white in colour and some places iron stained. It consists of friable, poorly sorted, fine to coarse grained sandstone and lies conformably on the Mamu Formation. It is a good aquifer to the study area. Field measurement shows that it has average dip amount of about 6.25o in the southwestern direction and average strike direction of about 5.6o Azimuth.
Results from sieve analysis show that Ajali Sandstone is poorly sorted, coarse skewed to nearly symmetrical, and very platykurtic to mesokurtic. The hydrochemical analysis of some of the surface water shows that the water is not fit for human consumption but could be used for other purposes. Among the sedimentary structures present in the area are cross bedding, laminae, joints, faults and biogenic structures. The area has a dendntic drainage pattern and has a high potential for groundwater as well as surface water supply. A significant geologic deposit found in the study area is coal. Others are sandstone, laterite, ironstone, shale and fire clay.
TABLE OF CONTENT
Title page - - - - - - - - i
Certification - - - - - - - ii
Dedication - - - - - - - iii
Acknowledgements - - - - - - iv
Abstract - - - - - - - - vi
Table of Content - - - - - - viii
List of figures - - - - - - - xii
List of tables - - - - - - - xv
List of plates - - - - - - - xvii
CHAPTER ONE
1.0 Location - - - - - - - 1
1.1 Accessibility - - - - - - 1
1.2 Objective and Scope of study - - - 2
1.3 method of Investigation - - - - 3
1.3.1 Desk study - - - - - - 3
1.3.2 Reconnaissance survey - - - - 4
1.3.3 Detailed Geologic Survey - - - - 4
1.3.4 Laboratory studies - - - - - 5
1.4 Problems encountered - - - - 5
1.5 Precautions - - - - - - 6
1.6 Literature Review - - - - - 7
CHAPTER TWO
2.0 Geomphology of the study Area - - - 11
2.1 Topography - - - - - - 11
2.2 Climate and Vegetation - - - - 12
2.3 Drainage - - - - - - - 13
2.4 Weathering - - - - - - 14
2.5 Erosion - - - - - - - 14
CHAPTER THREE
3.0 General Geology - - - - - 16
3.0.1 Geological History and Tectonics - - - 16
3.0.2 Basin fill - - - - - - - 17
3.0.3 Regional sedimentation pattern in the study area 18
3.1 Geology of the study area - - - - 18
3.1.1 Description of Lithologic Units - - - 20
3.1.1.1 Enugu shale - - - - - - 20
3.1.1.2Mamu Formation - - - - - 20
3.1.1.3 Ajali Sandstone - - - - - 28
3.1.1.4 Subsuface Lithostatgraphy - - - 35
3.2 Structural Geology - - - - - 37
3.2.1 Primary Sedimentary Structures - - - 38
3.2.2 Secondary Sedimentary Structures - - 40
3.3 Grain Size Analysis - - - - - 42
3.3.1 Statistical Size Subtraction Analysis - - 43
3.3.2 Summary of the Sieve Analysis Data - - 59
3.4 Plastic and Liquid Limit Test - - - 60
3.4.1 Plastic Limit Test - - - - - - 60
3.4.2 Liquid Limit Test - - - - - - 62
CHAPTER FOUR
4.0 Hydrogeology and Environmental Geology - 66
4.1 Hydrogeology - - - - - - 66
4.1.1 Surface Water Hydrology - - - - 66
4.1.2 Groundwater Hydrology - - - - 67
4.2 Hydrogeochemistry - - - - - 70
4.2.1 PH - - - - - - - - 71
4.2.2 Hardness - - - - - - 71
4.2.3 Iron - - - - - - - - 72
4.2.4 Coliform count - - - - - - 72
4.2.5 Manganese - - - - - - 73
4.3 Environmental Geology - - - - 77
4.3.1 Weathering - - - - - - 77
4.3.2 Geotechnic - - - - - - 78
4.3.3 Erosion - - - - - - - 78
4.3.3.1 Erosion Control Measure - - - - 79
4.3.4 Quarry - - - - - - - 80
4.3.5 Pollution and Contamination - - - - 81
CHAPTER FIVE
5.0 Economic Geology - - - - - 83
5.1 Coal - - - - - - - - 83
5.1.2 Important of Coal Mining - - - - 85
5.1.3 Coal as a Source Rock - - - - - 86
5.2 Shale and Clay - - - - - - 86
5.3 Sandstone/sands - - - - 88
5.4 Laterites - - - - - - - 89
Summary and Conclusion - - - - 90
Summary - - - - - - 90
Conclusion - - - - - - 92
References - - - - - - 93
LIST OF FIGURES
Fig. 1 Geologic map of Enugu – Ngwo and Environs
Fig. 2 Accessibility map of the study area
Fig. 3 Map of Enugu showing the study area
Fig. 4 Diagram showing cross a section of Enugu Escarpment
Fig. 5 Map showing wet season winds and rainfall
Fig. 6 Map showing dry season winds and rainfall
Fig. 7 Map of Nigeria showing natural vegetation
Fig. 8 Map showing the drainage pattern of the area
Fig. 9 Tectonic map of southeastern Nigeria during the Albian – Santonian
Fig. 10 Tectonic map of southeastern Nigeria during the campanian to Eocere
Fig. 11 Geological sketch map of Eastern Nigeria
Fig. 12 Diagram showing a section of Mamu formation around Milliken Hill Enugu – Ngwo 23
Fig. 13 Outcrop section of Mamu at Ekulu River 25
Fig. 14 Outcrop section of Mamu Formation along Enugu-Onitsha expressway 25
Fig. 15 Outcrop section of Mamu along PRODA road 26
Fig. 16 Outcrop section of A
